Liquid expulsion subsystem having orientation responsive pump

ABSTRACT

A subsystem which permits the temporary continued flow of a liquid (such as a fuel) from a tank, even during periods when, due to the physical orientation of the tank (such as when the tank is, for example, tilted or is in an inverted position), the flow of the liquid would ordinarily stop completely, because the liquid uncovers the outlet of the tank, or the liquid otherwise &#39;&#39;&#39;&#39;runs away&#39;&#39;&#39;&#39; from the outlet. The subsystem, as adapted for use with hydrazine in a propellant feed system, includes: a tank containing hydrazine and having an outlet in the lower portion thereof; a source of gas under high pressure connected to the tank; and, an expulsion assembly positioned in the lower portion of the tank, and above the outlet of the tank. The expulsion assembly has cooperating elements, including a diaphragm of flexible material, preferably plastic, which together with the walls of the tank form, define, and limit a &#39;&#39;&#39;&#39;trapping chamber&#39;&#39;&#39;&#39; part of the lower portion of the tank. When the tank is in its usual, and normal, bottom-down position, the expulsion assembly permits normal gravitational flow of the hydrazine from the entire tank. When the tank is in an orientation which would ordinarily result in the discontinuance of flow of the hydrazine therefrom, the expulsion assembly permits the continued temporary flow of the hydrazine by expelling that volume of hydrazine which is located within (and is &#39;&#39;&#39;&#39;trapped&#39;&#39;&#39;&#39; in) the &#39;&#39;&#39;&#39;trapping chamber&#39;&#39;&#39;&#39; part of the tank and is under the flexible plastic diaphragm.

United States Patent Barber [14 11 3,843,024 [4 11 Oct. 22, 1974 LIQUIDEXPULSION SUBSYSTEM HAVING 1 ORIENTATION RESPONSIVE PUMP [75] Inventor:Hartley E. Barber, Sylmar, Calif.

[73] Assignee: The United States of America as represented by theSecretary of the Air Force, Washington, DC. 1

[221 Filed: Oct. 26, 1972 [21] Appl. No.: 301,029

[52] US. Cl 222/207, 222/386.5, 417/118 [51] Int. Cl B67d 47/34 [58]Field of Search 222/207, 209, 386.5;

[56] References Cited UNITED STATES PATENTS 6/1963 Barnes ZZZ/386.5 x2/1966 Christian et al. 222/207 x Primary ExaminerRobert B; ReevesAssistant Examiner-David A. Scherbel Attorney, Agent, or Firm -l-larryA. Herbert, Jr.; Arsen Tashijian ing periods when, due to the physicalorientation of the tank (such as when the tank is, for example, tiltedor is in an inverted position), the flow of the liquid would ordinarilystop completely, because the liquid uncovers the outlet of the tank, orthe liquid otherwise runs away" from the outlet. The subsystem, asadapted for use with hydrazine in a propellant feed system, includes: atank containing hydrazine and having an outlet in the lower portionthereof; a source of gas under high pressure connected to the tank; and,an expulsion assembly positioned in the lower portion of the tank, andabove the outlet of the tank. The expulsion assembly has cooperatingelements, including a diaphragm of flexible material, preferablyplastic, which together with the walls of the tank form, define, andlimit a trapping chamber part'of theflower portion of the tank. When thetank is in its usual, and normal, bottom-down position, theexpulsion'assembly permits normal gravitational flow of the hydrazinefrom the entire tank. When the tank is in an orientation which wouldordinarily result in the discontinuance of flow of the hydrazinetherefrom, the expulsion assembly permits the continued temporary flowof the hydrazine by expelling that volume of hydrazine which is locatedwithin (and istrapped" in) the .trapping chamber part of the tank andisunder the flexible plastic diaphragm.

3 Claims, 2 Drawing Figures PAlimmnmzzrsu ww mm mSSOm mqmu LIQUIDEXPULSION SUBSYSTEM HAVING ORIENTATION RESPONSIVE PUMP BACKGROUND OF THEINVENTION aptation described herein of my invention is by way ofillustration only, and is not by way of any limitation.

In some propellant feed systems, such as those for use in aerospaceapplications (e.g., use in spacecraft, aircraft, missiles, and thelike), it often happens that, during in-flight maneuvering within theplanetary gravitational field, the liquid propellant reservoir, such asa tank, is physically reoriented from its usual and normal bottom-downposition to a tilted, or even to an inverted, position. As a result, theflowof the liquid, whether it be a monopropellant or in the case of abipropellant, the liquid fuel or the liquid oxidizer thereof, willdiscontinue (i.e., stop completely), because the liquid in the reservoiruncovers, or runsaway from, the reservoir liquid outlet, which isconventioally located in the lower portion of the reservoir, usually atthe bottom thereof. The consequences of such liquid starvation arehighly undesirable and, in certain situations which are readily apparentto those in the art, may be disastrous and tragic. i

There is, therefore, a constant and genuine need in the liquid supplysystem art and, more specifically, in the propellant feed system art fora component thereof, such as a subsystem, to assure continued flow ofthe liquid in the liquid propellant reservoir to the user component,such as an auxiliary power unit, irrespective of the orientation orattitude of the reservoir, even if such continued flow is only temporary(i.e., a limited time, such as 0.5 seconds).

l have invented a liquid expulsion subsystem which fullfils thisneed;and, therefore, I have significantly advanced the state-of-the-art.

SUMMARY OF THE INVENTION This invention pertains to a unique liquidexpulsion subsystem, as adapted for use in a propellant feed system,which will permit the continued flow of the liquid within the reservoirof the subsystem, irrespective of the orientation or attitude of thereservoir.

Therefore, the principal object of this invention is to provide such aunique (and, new, useful and unobvious) liquid expulsion subsystem.

Another object of this invention is to provide such a liquid expulsionsubsystem which, in addition to its unique fundamental functionalfeatures, is also simple in structure and, therefore, is economical tomanufacture, and further is completely reliable and, therefore, is foolproof.and fail safe in operation.

These objects, and other equally important and related objects, of thisinvention will become readily apparent after a consideration of thedescription of the invention and reference to the drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view, insimplified schematic form, partially in cross section and partiallyfragmented, of a preferred embodiment of my inventive I 2 subsystem, asadapted for use in a propellant feed system, and with FIG. 1 alsoshowing therein in phantom the position of one component of my inventivesubsystem immediately after the completion of the expulsion action;

FIG. 2 is a side elevation view, in simplified schematic form, in crosssection, enlarged, in detail, and not to scale, of a selected portion ofmy inventive subsystem.

DESCRIPTION OF THE PREFERRE EMBODIMENT With reference to FIG. 1, thereinis shown, in a side elevation view, in simplified schematic form,partially in cross section and partially fragmented, a preferredembodiment of my invention, as adapted for use in a propellant feedsystem.

The preferred embodiment of my invention, the unique liquid expulsionsubsystem 10 as shown in FIG. 1, is for'use in a propellant feed systemwherein hydrazine is the liquid fuel, and the liquid expulsion subsystem10 is for use in expelling, or continuing the flow of, the hydrazine.

The liquid expulsion subsystem 10 includes: a reservoir or tank 11 ofliquid-impervious (i.e., in this case,

hydrazine-impervious) material, and tank 11 has a top surface 12, abottom surface 13, and internal surface 14, an upper portion 15, a lowerportion 16, a first inlet 17, a second inlet 18, and an outlet 19located in the lower portion 16 of tank 11; a source 20 of gas 21 underhigh pressure (e.g., 45 psi), with source 20 having an outlet 22; afirst hollow conduit 30 which has two ends 31 and 32, with one end 31connected to the outlet 22 of the gas source 20, and with the other end32 connected to the second inlet 18 of tank 11; valving means, such asvalve 33, disposed between the outlet of the source 20 of gas'2l andthe: second inlet of tank 11 and connected to first hollow conduit 30,for controlling the flow of gas 21 from source 20, through first conduit30, and into tank 11; and, a liquid expulsion assembly 40 which ispositioned within the lower portion 16 0f tank 11 and above outlet 19 ofsaid tank 11.

Liquid expulsion assembly 40 comprises: a lip seal ring 50 which has alip" or mating surface 51 (also referred to herein as the sealingsurface), and which has a periphery S2, and also which is positionedwith the periphery 52 abutting with, and sealingly attached (i.e., insealing contact) by suitable means to, the internal surface 14 of tank11 so as to permit movement of the ring 60 with respect to the surface51; a perforated ring 60 which has perforations, such as 61 and 62, and

which has a periphery 63, and which is positioned so that it 60 is belowof, and essentially parallel to lip seal ring 50, with the periphery 63abutting with, and sealingly attached (i.e., in sealing contact) bysuitable means to, the internal surface 14 of tank 11 so as to permitmovement of the ring 60 with respect to the surface 51 of the ring 50; arigid seal ring (hereinafter referred to as the seal ring) which issmaller in size than perforated ring 60, and which has an innerperiphery 7 1, and an upper surface 72, and which is disposed betweenperforated ring 60 and lip seal ring 50, and which abuts with, and isattached by suitable means to, the perforated ring 60; a flexiblediaphragm 80, preferably made of plastic, which said diaphragm has anupper surface 81, a lower surface 82, a periphery 83, and a centrallylocated opening 84, such as a pinhole,

with the diaphragm so positioned that the periphery 83 is abutting with,and is attached by suitable means to, the seal ring 70 at the innerperipheral surface 71 of the ring 70; and, a float ring 90 which isattached to the upper surface 81 of the diaphragm 80 and which surroundsthe central opening (or pinhole) 84 of the diaphragm 80.

Also shown in FIG. 1 are: second hollow conduit 34 which has-two ends,with one end 35 connected to first inlet 17 of tank 11, and with theother end not shown in the interest of maintaining simplicity of thedrawing; and, means for closing inlet 17, such as valve 36 which isdisposed between inlet 17 and a source of hydrazine (which source alsois not shown to maintain simplicity), and which said valve 36 isconnected to second hollow conduit 34.

It is here to be noted: that valve 33 also, in effect, closes and openssecond inlet 18; that valve 36 also controls the flow of hydrazine (orother liquid used), with the flow thereof shown in FIG. 1 by arrowshaving reference numeral 100; that the above reference to seal ring 70as being rigid is intended only as a comparative term, in the sense thatthe diaphragm 80 (which is attached to the ring 70) is flexible; thatseal ring 70 has an effective density slightly greater than the liquidin the tank 11 (e.g., if hydrazine is the liquid in the tank and isassumed, to have a density of 1.0, then thepreferred density of the sealring is about 1.3); that upper surface 72 of ring 70 is directly opposed(i.e., is directionally opposite) to the lip or mating surface (orsealing surface) 51 of lip seal ring 50; and, that the liquid expulsionassembly40, as a whole, together with the internal surface 41 (orsidewalls, if any) of the reservoir or tank 11, form, define, and limita trapping chamber part, generally designated as 16A, of the lowerportion 16 of tank 11.

It is also here to be noted that a selected portion of the liquidexpulsion assembly 40 of my invention is generally designated A" in FIG.1; is shown in FIG. 2; and, will be discussed hereinafter.

With reference to FIG. 2, therein is shown, in a side elevation view,insimplified schematic form, in cross section, in detail, enlarged, andnot to scale, a portion of the liquid expulsion assembly 40 of myinventive liquid expulsion subsystem 10, as adapted for use in apropellant feed system, which said portion is designated as A both inFIGS. 1 and 2.

More specifically, shown in FIG. 2 are: lip seal ring 50 with lip orsealing surface 51; seal ring 70 with inner periphery 71 and with uppersurface 72; and, flexible diaphragm 80.

MODE OF OPERATION OF THE PREFERRED EMBODIMENT The mode of operation ofmy inventive subsystem 10, and of the liquid expulsion assembly 40,thereof, is selfevident and is easily understood from the foregoingdescription, coupled with reference to the drawings.

As a preliminary matter, it is to be remembered that the preferredembodiment 10, FIG. I, is an adaptation for use in a propellant feedsystem wherein my liquid expulsion subsystem 10 is for use in expelling,and in continuing the flow of, hydrazine (a liquid or one of the liquidsused) in the propellant system.

It is to be assumed that, at this point, the tank 11 is in its normal,bottom-down position.

The liquid, i.e., the hydrazine, is introduced into the tank 11 bysuitable means, such as from a source of hydrazine which is connected tconduit 34. With the valve 36 in an open mode e hydrazine 100 flowsthrough conduit 34, through first inlet 17 (which is, in effect,closeable by positioning valve 36 in the closed mode), and into tank 11to the desired height or level, or in the desired quantity. First inlet17 is then closed by closing valve 36, and the inflow of the hydrazine100 ceases.

Duringthis filling process, the hydrazine also goes to the lower portion16 of the tank 11, including the trapping chamber" part 16A, by flowingaround the diaphragm 80, past the lip 51 of lip seal ring 50, over theupper surface 72 of seal ring 70, and through the perforations, such as61 and 62, of perforated ring 60. The tank 11 is pressurized, and thehydrazine 100 is kept under pressure, by use of gas pressure source 20,gas 21 flowing therefrom, conduit 30, valve 33, and second outlet 18 oftank 11. The pressure exerted is preferably approximately 45 psi. Atthis time the diaphragm is in the float position shown in FIG. 1, withthe float ring providing buoyancy. Additionally, at this time, thegravitational force is a positive 1.0 $60.,

Upon demand, and by the use of suitable means, the hydrazine flowsthrough outlet 19 of tank 11 to the user component, such as an auxiliarypower unit, because of the gravitational force and the pressure ertedupon the hydrazine 100.

.When, however, the tank is reoriented from its normal bottomdownattitude, such as when the tank is inverted, and as a result there isreverse or negative G" loading, the flow of the hydrazine 100 (whichwould ordinarily stop completely, because the hydrazine 100 uncovers theoutlet 19) continues, due to the unique structure of my invention 10. I

What sequentially, and physically, occurs is that, with the reverse Gloading, the seal ring 70 falls (i.e., rises in the bottom-down attitudeshown in FIGS. 1 and 2) and the upper surface thereof 72 sealingly restsagainst (and mates with) the lip 51 of lip seal ring 50, primarily dueto the hydraulic pressure of the hydrazine 100. A volumetric amount ofhydrazine 100 is, thereby, trapped in trapping chamber 16A. Bubbles, ifany, escape through central opening 84 of diaphragm 80. The tankpressure, discussed hereinabove, is felt by and on the diaphragm 80, butis not felt by and on the seal ring 70, which is temporarily restingagainst the lip seal ring 50. Positive expulsion of the hydrazine 100trapped in trapping chamber 16A continues through outlet 19 because ofthe gas pressure-related collapse of flexible diaphragm 80, as shown bythe phantom line in FIG. 1, through its 80 displacement volume, intotrapping chamber 16A. This displacement volume is generallydesignated asB in FIG. 2; and, said volume is represented two-dimensionally in saidFIG. 2 by the area bounded by the curved line 84 identifying thediaphragm in the float position, and by the curved phantom line in saidFigure which represents the collapsed position of the diaphragm 80immediately after the completion of the positive expulsion action.

As can be easily seen, the flow of the hydrazine 100 will continuetemporarily for the needed or desired time, and the highly undesirablepropellant starvation will be prevented.

It can also be easily seen that the diaphragm displace- CONCLUSlON It isclearly evident from the above description, and from the drawingsherein, that all of the objects of this invention have been attained.Therefore, it is not believed necessary to again set forth the objects,and the other objects related thereto, of the invention, and show howeach of the objects has been achieved by, and with the use of, theinvention. Suffice it to say that, in addition to its fundamentalinventive structural features, the invention is simple, economical tomanufacture, completely reliable, and foolproof and fail safe."

In addition, while there have been shown and described the fundamentalfeatures of my invention, as adapted for a specific use and as appliedto a particular preferred embodiment, it is to be understood thatvarious other adaptations, embodiments, substitutions, omissions,additions, and the like, can be made by those of ordinary skill in theart without departing from the spirit of my invention. In essence, myliquid expulsion subsystem, and particularly my liquid expulsionassembly thereof, can be used, or can be adapted to be used, to providepositive expulsion of any liquid from a reservoir under adverse .Gconditions within a planetary gravitational field.

What is claimed is:

1. A liquid expulsion subsystem, comprising:

a. a tank made of liquid-impervious material, for containing a liquidwhich is to be expelled from said tank, wherein said tank includes a topsurface, a bottom surface, and an internal surface, and with said tankhaving therein an upper portion and a lower portion, and also with saidtank having a first closeable inlet to permit the inflow of the liquidinto the tank, a second inlet, and an outlet to permit the outflow ofthe liquid from the tank, with said outlet located in the said lowerportion of the tank;

b. a source of gas under high pressure, with said surface having anoutlet;

c. a first hollow conduit having two ends, with one end connected to theoutlet of said source of gas under high pressure, and with the other endconnected to the second inlet of said tank;

d. valving means, disposed between the outlet of said source of gasunder high pressure and the second inlet of said tank, and connected tosaid first hollow conduit, for controlling the flow of the gas from saidgas source, through said first hollow conduit, and into said tank;

e. and, a liquid expulsion assembly, positioned within the said lowerportion of said tank and above said outlet of said tank, comprising:

1. a lip seal ring having a periphery, with said periphery abuttingwith, and sealingly attached by suitable means to, the internal surfaceof said tank;

2. a perforated ring havinga periphery and positioned below of, andessentially parallel to, said lip seal ring, with said peripheryabutting with, and sealingly attached by suitable means to, the internalsurface of said tank;

3. a seal ring, smaller in size than said perforated ring, and having aninner peripheral surface, with said seal ring disposed between saidperforated ring and said lip seal ring, and with said seal ring abuttingwith, and attached to, said perforated r1ng;

4. a flexible diaphragm having an upper surface, a

lower surface, a periphery, anda centrally located opening, with saidperiphery abutting with, and attached by suitable means to, the innerperipheral surface of said-seal ring;

5. and, a float ring attached to the upper surface of said diaphragm andsurrounding said central opening of said diaphragm.

2. The liquid expulsion subsystem, as set forth in claim 1, wherein saidflexible diaphragm of said liquid expulsion assembly is made of plastic.

3. The liquid expulsion subsystem, as set forth in claim 1, wherein theeffective density of said seal ring of said liquid expulsion assembly isof an effective density slightly greater than the liquid to be containedby,

and in, said tank.

1. A liquid expulsion subsystem, comprising: a. a tank made ofliquid-impervious material, for containing a liquid which is to beexpelled from said tank, wherein said tank includes a top surface, abottom surface, and an internal surface, and with said tank havingtherein an upper portion and a lower portion, and also with said tankhaving a first closeable inlet to permit the inflow of the liquid intothe tank, a second inlet, and an outlet to permit the outflow of theliquid from the tank, with said outlet located in the said lower portionof the tank; b. a source of gas under high pressure, with said surfacehaving an outlet; c. a first hollow conduit having two ends, with oneend connected to the outlet of said source of gas under high pressure,and with the other end connected to the second inlet of said tank; d.valving means, disposed between the outlet of said source of gas underhigh pressure and the second inlet of said tank, and connected to saidfirst hollow conduit, for controlling the flow of the gas from said gassource, through said first hollow conduit, and into said tank; e. and, aliquid expulsion assembly, positioned within the said lower portion ofsaid tank and above said outlet of said tank, comprising:
 1. a lip sealring having a periphery, with said periphery abutting with, andsealingly attached by suitable means to, the internal surface of saidtank;
 2. a perforated ring having a periphery and positioned below of,and essentially parallel to, said lip seal ring, with said peripheryabutting with, and sealingly attached by suitable means to, the internalsurface of said tank;
 3. a seal ring, smaller in size than saidperforated ring, and having an inner peripheral surface, with said sealring disposed between said perforated ring and said lip seal ring, andwith said seal ring abutting with, and attached to, said perforatedring;
 4. a flexible diaphragm having an upper surface, a lower surface,a periphery, and a centrally located opening, with said peripheryabutting with, and attached by suitable means to, the inner peripheralsurface of said seal ring;
 5. and, a float ring attached to the uppersurface of said diaphragm and surrounding said central opening of saiddiaphragm.
 2. a perforated ring having a periphery and positioned belowof, and essentially parallel to, said lip seal ring, with said peripheryabutting with, and sealingly attached by suitable means to, the internalsurface of said tank;
 2. The liquid expulsion subsystem, as set forth inclaim 1, wherein said flexible diaphragm of said liquid expulsionassembly is made of plastic.
 3. The liquid expulsion subsystem, as setforth in claim 1, wherein the effective density of said seal ring ofsaid liquid expulsion assembly is of an effective density slightlygreater than the liquid to be contained by, and in, said tank.
 3. a sealring, smaller in size than said perforated ring, and having an innerperipheral surface, with said seal ring disposed between said perforatedring and said lip seal ring, and with said seal ring abutting with, andattached to, said perforated ring;
 4. a flexible diaphragm having anupper surface, a lower surface, a periphery, and a centrally locatedopening, with said periphery abutting with, and attached by suitablemeans to, the inner peripheral surface of said seal ring;
 5. and, afloat ring attached to the upper surface of said diaphragm andsurrounding said central opening of said diaphragm.